Answer:
The dimensions of the smallest piece that can be used are: 10 by 20 and the area is 200 square inches
Step-by-step explanation:
We have that:

Let the dimension of the paper be x and y;
Such that:


So:

Substitute 128 for Area

Make x the subject

When 1 inch margin is at top and bottom
The length becomes:


When 2 inch margin is at both sides
The width becomes:


The New Area (A) is then calculated as:

Substitute
for x

Open Brackets

Collect Like Terms



To calculate the smallest possible value of y, we have to apply calculus.
Different A with respect to y

Set

This gives:

Collect Like Terms

Multiply through by 


Divide through by 2

Take square roots of both sides



Recall that:



Recall that the new dimensions are:


So:




To double-check;
Differentiate A'




The above value is:

This means that the calculated values are at minimum.
<em>Hence, the dimensions of the smallest piece that can be used are: 10 by 20 and the area is 200 square inches</em>
<span>7.25 = 7 and 25/100 = 7 and 1/4</span>
Answer:
$3.51
Step-by-step explanation:
1 pound is $2.39 so divide by 2 and round up to the nearest whole number which is $1.12. Add $1.12(The cost of 0.5 pounds) to $2.39(The cost of 1 pound) to get $3.51 as your total.
The last answer is the correct one.
If it does not make sense ask for clarification.